Characterization of antibodies targeting severe fever with thrombocytopenia syndrome virus glycoprotein Gc.

Severe fever with thrombocytopenia syndrome (SFTS) is a hemorrhagic fever caused by SFTS virus (SFTSV), which is primarily found in East Asian countries. Despite its high mortality rate and increasing incidence, no vaccines or therapeutics have yet been approved for use against SFTS. Antibody drugs have shown promise in treating lethal infectious diseases that currently have no established treatments. In the case of SFTS, however, only a limited amount of research has been done on SFTSV-neutralizing antibodies targeting the transmembrane proteins Gn and Gc, which play critical roles in viral infection. This study focuses on the production and characterization of antibodies targeting the SFTSV Gc protein. Monoclonal antibodies against Gc were generated through immunization of mice, and their antiviral activity was evaluated. Three out of four anti-Gc antibody clones from this study demonstrated dose-dependent SFTSV neutralization activity, two of which exhibited a synergistic effect on the neutralization activity of the anti-Gn antibody clone Mab4-5. Further studies are necessary to identify key sites on the SFTSV glycoprotein and to develop novel agents as well as antibodies with diverse mechanisms of action against SFTSV.

Bovine lactoferrin increases the poly(I:C)-induced antiviral response in vitro.

Bovine lactoferrin (bLF) is a naturally occurring glycoprotein with antibacterial and antiviral activities. We evaluated whether bLF can prevent viral infections in the human intestinal epithelial cell line Caco-2. To assess antiviral responses, we measured the levels of interferon (IFN) expression, IFN-stimulated gene expression, and infection with a pseudotyped virus bearing either severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) spike protein or vesicular stomatitis virus (VSV)-G protein after treatment of cells with both bLF and polyinosinic-polycytidylic acid, an analog of double-stranded RNA that mimics viral infection. Combination treatment of cells with both bLF and polyinosinic-polycytidylic acid increased mRNA and protein expression of several IFN genes (IFNB, IFNL1, and IFNL2) and IFN-stimulated genes (ISG15, MX1, IFITM1, and IFITM3) in Caco-2 cells. However, treatment with bLF alone did not induce an antiviral response. Furthermore, combination treatment suppressed infection of the SARS-CoV-2 pseudotyped virus more efficiently than did bLF treatment alone, even though combination treatment increased the expression of mRNA encoding ACE2. These results indicate that bLF increases the antiviral response associated with the double-stranded RNA-stimulated signaling pathway. Our results also suggest that bLF and double-stranded RNA analogs can be used to treat viral infections, including those caused by SARS-CoV-2.

SARS-CoV-2 RNAemia with a higher nasopharyngeal viral load is strongly associated with disease severity and mortality in patients with COVID-19.

This study aimed to determine the frequency of SARS-CoV-2 RNA in serum and its association with the clinical severity of COVID-19. This retrospective cohort study performed at Toyama University Hospital included consecutive patients with confirmed COVID-19. The prevalence of SARS-CoV-2 RNAemia and the strength of its association with clinical severity variables were examined. Fifty-six patients were included in this study. RNAemia was detected in 19.6% (11/56) patients on admission, and subsequently in 1.0% (1/25), 50.0% (6/12), and 100.0% (4/4) moderate, severe, and critically ill patients, respectively. Patients with RNAemia required more frequent oxygen supplementation (90.0% vs. 13.3%), ICU admission (81.8% vs. 6.7%), and invasive mechanical ventilation (27.3% vs. 0.0%). Among patients with RNAemia, the median viral loads of nasopharyngeal (NP) swabs that were collected around the same time as the serum sample were significantly higher in critically ill (5.4 log10 copies/µl; interquartile range [IQR]: 4.2-6.3) than in moderate-severe cases (2.6 log10 copies/µl; [IQR: 1.1-4.5]; p = 0.030) and were significantly higher in nonsurvivors (6.2 log10 copies/µl [IQR: 6.0-6.5]) than in survivors (3.9 log10 copies/µl [IQR: 1.6-4.6]; p = 0.045). This study demonstrated a relatively high proportion of SARS-CoV-2 RNAemia and an association between RNAemia and clinical severity. Moreover, among the patients with RNAemia, the viral loads of NP swabs were correlated with disease severity and mortality, suggesting the potential utility of combining serum testing with NP tests as a prognostic indicator for COVID-19, with higher quality than each separate test.

Evaluation of SARS-CoV-2 neutralizing antibodies using a vesicular stomatitis virus possessing SARS-CoV-2 spike protein.

BACKGROUND: SARS-CoV-2 is a novel coronavirus that emerged in 2019 and is now classified in the genus Coronavirus with closely related SARS-CoV. SARS-CoV-2 is highly pathogenic in humans and is classified as a biosafety level (BSL)-3 pathogen, which makes manipulating it relatively difficult due to its infectious nature. METHODS: To circumvent the need for BSL-3 laboratories, an alternative assay was developed that avoids live virus and instead uses a recombinant VSV expressing luciferase and possesses the full length or truncated spike proteins of SARS-CoV-2. Furthermore, to measure SARS-CoV-2 neutralizing antibodies under BSL2 conditions, a chemiluminescence reduction neutralization test (CRNT) for SARS-CoV-2 was developed. The neutralization values of the serum samples collected from hospitalized patients with COVID-19 or SARS-CoV-2 PCR-negative donors against the pseudotyped virus infection evaluated by the CRNT were compared with antibody titers determined from an enzyme-linked immunosorbent assay (ELISA) or an immunofluorescence assay (IFA). RESULTS: The CRNT, which used whole blood collected from hospitalized patients with COVID-19, was also examined. As a result, the inhibition of pseudotyped virus infection was specifically observed in both serum and whole blood and was also correlated with the results of the IFA. CONCLUSIONS: In conclusion, the CRNT for COVID-19 is a convenient assay system that can be performed in a BSL-2 laboratory with high specificity and sensitivity for evaluating the occurrence of neutralizing antibodies against SARS-CoV-2.

Elucidation of N 1-methyladenosine as a Potential Surrogate Biomarker for Drug Interaction Studies Involving Renal Organic Cation Transporters.

Endogenous substrates are emerging biomarkers for drug transporters, which serve as surrogate probes in drug-drug interaction (DDI) studies. In this study, the results of metabolome analysis using wild-type and Oct1/2 double knockout mice suggested that N 1-methyladenosine (m1A) was a novel organic cation transporter (OCT) 2 substrate. An in vitro transport study revealed that m1A is a substrate of mouse Oct1, Oct2, Mate1, human OCT1, OCT2, and multidrug and toxin exclusion protein (MATE) 2-K, but not human MATE1. Urinary excretion accounted for 77% of the systemic elimination of m1A in mice. The renal clearance (46.9 ± 4.9 ml/min per kilogram) of exogenously given m1A was decreased to near the glomerular filtration rates by Oct1/2 double knockout or Mate1 inhibition by pyrimethamine (16.6 ± 2.6 and 24.3 ± 0.6 ml/min per kilogram, respectively), accompanied by significantly higher plasma concentrations. In vivo inhibition of OCT2/MATE2-K by a single dose of 7-[(3R)-3-(1-aminocyclopropyl)pyrrolidin-1-yl]-1-[(1R,2S)-2-fluorocyclopropyl]-8-methoxy-4-oxoquinoline-3-carboxylic acid in cynomolgus monkeys resulted in the elevation of the area under the curve of m1A (1.72-fold) as well as metformin (2.18-fold). The plasma m1A concentration profile showed low diurnal and interindividual variation in healthy volunteers. The renal clearance of m1A in younger (21-45 year old) and older (65-79 year old) volunteers (244 ± 58 and 169 ± 22 ml/min per kilogram, respectively) was about 2-fold higher than the creatinine clearance. The renal clearances of m1A and creatinine were 31% and 17% smaller in older than in younger volunteers. Thus, m1A could be a surrogate probe for the evaluation of DDIs involving OCT2/MATE2-K. SIGNIFICANCE STATEMENT: Endogenous substrates can serve as surrogate probes for clinical drug-drug interaction studies involving drug transporters or enzymes. In this study, m1A was found to be a novel substrate of renal cationic drug transporters OCT2 and MATE2-K. N 1-methyladenosine was revealed to have some advantages compared to other OCT2/MATE substrates (creatinine and N 1-methylnicotinamide). The genetic or chemical impairment of OCT2 or MATE2-K caused a significant increase in the plasma m1A concentration in mice and cynomolgus monkeys due to the high contribution of tubular secretion to the net elimination of m1A. The plasma m1A concentration profile showed low diurnal and interindividual variation in healthy volunteers. Thus, m1A could be a better biomarker of variations in OCT2/MATE2-K activity caused by inhibitory drugs.

Effects of magnesium oxide on pharmacokinetics of L-dopa/carbidopa and assessment of pharmacodynamic changes by a model-based simulation.

BACKGROUND: Magnesium oxide (MgO) is often co-prescribed with L-dopa/carbidopa (LDCD) to improve constipation in Parkinson's disease patients. The mixing of L-dopa and MgO has been shown to degrade L-dopa; however, there is no interaction study on humans. We proposed mechanisms for the interaction between LDCD and MgO and conducted pharmacokinetic studies on rats and humans. To assess pharmacodynamic changes with the MgO treatment, we applied a model-based meta-analysis (MBMA). METHODS: The effects of MgO on the stabilities of L-dopa and carbidopa were evaluated in in vitro studies. We conducted pharmacokinetic interaction studies of MgO and LDCD on rats and healthy volunteers. A clinical study was conducted with an open-label, non-randomized, single-arm, and two-phase study. In MBMA, we constructed a population pharmacokinetic/pharmacodynamic model of L-dopa and predicted the effects of the MgO treatment on the pharmacodynamics of L-dopa. RESULTS: In vitro results suggested that carbidopa was unstable under alkaline pH conditions. Reductions in plasma LDCD concentrations were observed after oral-MgO/oral-LDCD, but not in oral-MgO/i.v.-LDCD treatments in rats, suggesting that the gastrointestinal tract is an interaction site. A healthy volunteer study showed that MgO was also associated with significant decreases of 35.3 and 80.9% in the AUC0-12 of L-dopa and carbidopa, respectively. A model-based simulation suggested that the MgO treatment was undesirable for the effectiveness of L-dopa. CONCLUSIONS: This is the first study to show a clear pharmacokinetic interaction between LDCD and MgO in humans. Further investigations to confirm the effects of MgO on the pharmacodynamics of L-dopa are required.

Laryngeal squamous cell papilloma is highly associated with human papillomavirus.

OBJECTIVE: To delineate the association between characteristics of adult-onset laryngeal squamous cell papilloma and human papillomavirus (HPV) infection. METHODS: Clinical records and paraffin-embedded specimens of 77 papilloma patients who had been treated between 1998 and 2014 were collected. Of the 77 cases, 34 were identified in the larynx, 28 in the oral cavity and 15 in the oropharynx. Specimens were investigated by polymerase chain reaction (PCR) to detect HPV 6, 11, 16, 18, 31, 33, 35, 52b and 58, and immunohistochemical (IHC) staining for anti-p16INK4a antibody. RESULTS: In 21 cases (61.8%) with laryngeal squamous cell papilloma, various types of HPV were detected: 14 cases (41.2%) were positive of high-risk HPV, 18 (52.9%) were positive of low-risk HPV and 11 (32.4%) were positive of both high-risk HPV and low-risk HPV. Younger patients (<60 years) showed a higher rate of HPV infection than older patients. Among the 34 cases with laryngeal papilloma, no malignant transformation was observed during the study period. With IHC staining, positive expression of p16 was observed in 20 cases (58.8%). HPV infection and p16-expression were associated with the pathological finding of koilocytosis. Only four cases (14.3%) showed HPV-positivity in the oral cavity, and none of the 15 oropharyngeal cases were positive for HPV, and none of the oral cavity and oropharyngeal cases showed koilocytosis. Results of HPV-PCR and p16-IHC staining were significantly correlated each other. CONCLUSIONS: HPV infection is frequently associated with laryngeal squamous cell papilloma, and koilocytosis is a characteristic pathological finding. To the best of our knowledge, this is the first report which have described infections with multiple HPV types in laryngeal papilloma.

Clarification of the Mechanism of Clopidogrel-Mediated Drug-Drug Interaction in a Clinical Cassette Small-dose Study and Its Prediction Based on In Vitro Information.

Clopidogrel is reported to be associated with cerivastatin-induced rhabdomyolysis, and clopidogrel and its metabolites are capable of inhibiting CYP2C8 and OATP 1B1 in vitro. The objective of the present study was to identify the mechanism of clopidogrel-mediated drug-drug interactions (DDIs) on the pharmacokinetics of OATP1B1 and/or CYP2C8 substrates in vivo. A clinical cassette small-dose study using OATPs, CYP2C8, and OATP1B1/CYP2C8 probe drugs (pitavastatin, pioglitazone, and repaglinide, respectively) with or without the coadministration of either 600 mg rifampicin (an inhibitor for OATPs), 200 mg trimethoprim (an inhibitor for CYP2C8), or 300 mg clopidogrel was performed, and the area under the concentration-time curve (AUC) ratios (AUCRs) for probe substrates were predicted using a static model. Clopidogrel increased the AUC of pioglitazone (2.0-fold) and repaglinide (3.1-fold) but did not significantly change the AUC of pitavastatin (1.1-fold). In addition, the AUC of pioglitazone M4, a CYP2C8-mediated metabolite of pioglitazone, was reduced to 70% of the control by coadministration of clopidogrel. The predicted AUCRs using the mechanism-based inhibition of CYP2C8 by clopidogrel acyl-ß-glucuronide were similar to the observed AUCRs, and the predicted AUCR (1.1) of repaglinide using only the inhibition of OATP1B1 did not reach the observed AUCR (3.1). In conclusion, a single 300 mg of clopidogrel mainly inhibits CYP2C8-mediated metabolism by clopidogrel acyl-ß-glucuronide, but its effect on the pharmacokinetics of OATP1B1 substrates is negligible. Clopidogrel is expected to have an effect not only on CYP2C8 substrates, but also dual CYP2C8/OATP1B1 substrates as seen in the case of repaglinide.

Pharmacokinetics and pharmacodynamics of FSK0808 and Gran after single intravenous drip administration or single subcutaneous administration: comparative study in healthy Japanese adult male subjects.

FSK0808 is a recombinant human granulocyte colony-stimulating factor developed by Fuji Pharma Co., Ltd and Mochida Pharmaceutical Co., Ltd. as a biosimilar product of Gran®. We verified the pharmacokinetic/pharmacodynamic equivalence of FSK0808 and commercially available Gran® by a randomized crossover study of single intravenous dose (200 µg/m(2)) and single subcutaneous dose (400 µg/m(2)) in healthy Japanese adult male subjects. According to the bioequivalence guidelines, the area under the blood concentration - time curve by 48 hours after administration (AUC0-48) in a single intravenous drip (IVD) study, and AUC0-48 and maximum blood concentration (Cmax) in a single subcutaneous (SC) dose study were used as primary endpoints, and the pharmacodynamic parameters including absolute neutrophil count (ANC) or number of CD34 positive cells (CD34(+) cells) as secondary endpoints. The safety was evaluated based on the characteristics and incidence of adverse reactions. As a result, the 90% confidence interval (CI) of the difference in mean value for AUC0-48 among drugs ranged from log(0.8) to log(1.25), in the IVD study, and those for Cmax and AUC0-48 were within the range of log(0.8)-log(1.25) in the SC study. Those for secondary endpoints were all within the range of log(0.8)-log(1.25). Thus, the pharmacokinetics/pharmacodynamics of both drugs were considered equivalent for all routes of administration, and the profiles of adverse reactions were also very similar.

Korean, Japanese, and Chinese populations featured similar genes encoding drug-metabolizing enzymes and transporters: a DMET Plus microarray assessment.

BACKGROUND: Interethnic differences in genetic polymorphism in genes encoding drug-metabolizing enzymes and transporters are one of the major factors that cause ethnic differences in drug response. This study aimed to investigate genetic polymorphisms in genes involved in drug metabolism, transport, and excretion among Korean, Japanese, and Chinese populations, the three major East Asian ethnic groups. METHODS: The frequencies of 1936 variants representing 225 genes encoding drug-metabolizing enzymes and transporters were determined from 786 healthy participants (448 Korean, 208 Japanese, and 130 Chinese) using the Affymetrix Drug-Metabolizing Enzymes and Transporters Plus microarray. To compare allele or genotype frequencies in the high-dimensional data among the three East Asian ethnic groups, multiple testing, principal component analysis (PCA), and regularized multinomial logit model through least absolute shrinkage and selection operator were used. RESULTS: On microarray analysis, 1071 of 1936 variants (>50% of markers) were found to be monomorphic. In a large number of genetic variants, the fixation index and Pearson's correlation coefficient of minor allele frequencies were less than 0.034 and greater than 0.95, respectively, among the three ethnic groups. PCA identified 47 genetic variants with multiple testing, but was unable to discriminate ethnic groups by the first three components. Multinomial least absolute shrinkage and selection operator analysis identified 269 genetic variants that showed different frequencies among the three ethnic groups. However, none of those variants distinguished between the three ethnic groups during subsequent PCA. CONCLUSION: Korean, Japanese, and Chinese populations are not pharmacogenetically distant from one another, at least with regard to drug disposition, metabolism, and elimination.

Complete Genome Sequence of Corynebacterium ulcerans Strain TSU-28, Harboring Two Diphtheria Toxin Genes, Isolated from a Patient with Diphtheria-Like Symptoms.

Diphtheria toxin-producing Corynebacterium ulcerans is an emerging zoonotic pathogen that causes severe disease in humans. Here, we report the complete genome sequence of C. ulcerans strain TSU-28, harboring two diphtheria toxin genes, which was isolated from the throat of a patient with diphtheria-like symptoms in 2019 in Japan.

Inhibitors of cannabinoid receptor 1 suppress the cellular entry of Lujo virus.

Lujo virus (LUJV), which belongs to Mammarenavirus, family Arenaviridae, has emerged as a pathogen causing severe hemorrhagic fever with high mortality. Currently, there are no effective treatments for arenaviruses, including LUJV. Here, we screened chemical compound libraries of Food and Drug Administration (FDA)-approved drugs and G protein-coupled receptor-associated drugs to identify effective antivirals against LUJV targeting cell entry using a vesicular stomatitis virus-based pseudotyped virus bearing the LUJV envelope glycoprotein (GP). Cannabinoid receptor 1 (CB1) antagonists, such as rimonabant, AM251 and AM281, have been identified as robust inhibitors of LUJV entry. The IC50 of rimonabant was 0.26 and 0.53 µM in Vero and Huh7 cells, respectively. Analysis of the cell fusion activity of the LUJV GP in the presence of CB1 inhibitors revealed that these inhibitors suppressed the fusion activity of the LUJV GP. Moreover, rimonabant, AM251 and AM281 reduced the infectivity of authentic LUJV in vitro, suggesting that the antiviral activity of CB1 antagonists against LUJV is mediated, at least in part, by inhibition of the viral entry, especially, membrane fusion. These findings suggest promising candidates for developing new therapies against LUJV infections.

Pharmacogenomic/pharmacokinetic assessment of a four-probe cocktail for CYPs and OATPs following oral microdosing.

OBJECTIVES: To test whether the multiple phenotype and genotype relationships established using therapeutic dose, can be reproduced following oral microdosing using substrates of CYP2C9 (warfarin and glibenclamide), CYP2C19 (lansoprazole), CYP2D6 (dextromethorphan), and OATPs (glibenclamide). METHODS: A cocktail of test drugs was administered orally under the microdose in liquid or capsule form, and then a therapeutic dose of dextromethorphan was administered to 17 healthy subjects whose genotypes for CYPs and OATPs had been prescreened. Concentrations of the drugs and their metabolites were measured by LC-MS/MS. RESULTS: The AUC and t1/2 of glibenclamide following the microdosing tended to be higher and longer, respectively, in CYP2C9*1/*3 than CYP2C9*1/*1 subjects. In contrast, there were no significant differences in any of the pharmacokinetic parameters for warfarin between the two genotypes. For CYP2D6 following the therapeutic dose, there was good concordance between genotype and phenotype; however, such relationships disappeared after microdosing. For CYP2C19 following the microdosing, there were significant differences between EMs and PMs in the pharmacokinetic parameters of lansoprazole. The relative AUC0-12 ratio of lansoprazole in EMs and PMs was 1:3.3 - 4.3. Among test drugs, phenotypic measurements of lansoprazole accorded well with the CYP2C19 genotype at the microdose as well as therapeutic dose. CONCLUSIONS: The present study suggests that 1) the sampling strategy should be optimized according to pharmacokinetic profiles of the test drugs following oral microdosing, and 2) microdosing can be applied to the pharmacogenomic study of CYP-specific drugs.

Detection of Torque teno virus DNA in exhaled breath by polymerase chain reaction.

To determine whether exhaled breath contains Torque teno virus (TTV) or not, we tested exhaled breath condensate (EBC) samples by semi-nested PCR assay. We detected TTV DNA in 35% (7/20) of EBC samples collected from the mouth of one of the authors, demonstrating that TTV DNA is excreted in exhaled breath with moderate frequency. TTV DNA was detected also in oral EBC samples from 4 of 6 other authors, indicating that TTV DNA excretion in exhaled breath is not an exception but rather a common phenomenon. Furthermore, the same assay could amplify TTV DNA from room air condensate (RAC) samples collected at distances of 20 and 40cm from a human face with 40 (8/20) and 35% (7/20) positive rates, respectively. TTV transmission has been reported to occur during infancy. These distances seem equivalent to that between an infant and its household members while caring for the infant. Taken together, it seems that exhaled breath is one of the possible transmission routes of TTV. We also detected TTV DNA in 25% (10/40) of RAC samples collected at a distance of more than 180cm from any human face, suggesting the risk of airborne infection with TTV in a room.

A highly quantitative detection system for cell entry of human norovirus-like particles based on the complementation of NanoLuc luciferase.

Human norovirus (HuNoV) is the common cause of acute gastroenteritis worldwide. Norovirus-like particles (VLPs) have been applied to analyze virus-host cell interactions. This study established a highly quantitative detection system for HuNoV VLP entry into live cells based on the NanoLuc luciferase complementation. First, we generated a HiBiT-tagged VLP and examined VLP-HiBiT entry into Vero cells expressing LgBiT. The entry was saturable and competed by a non-labeled VLP, indicating the VLP-specific entry into the host cells. Upon comparison of the VLP-HiBiT entry among some cell lines, Caco-2 cells were found to be the most susceptible. The VLP-HiBiT entry was unaffected by treatment at an acidic pH value above 3.0 and was significantly reduced by heat treatment at 75°C for more than 2 min. These results reflected those of previous studies, indicating the stability of VLPs and binding to histo-blood group antigens at various pH ranges and temperatures and cellular tropism.

Pharmacokinetic and pharmacogenomic profiles of telmisartan after the oral microdose and therapeutic dose.

OBJECTIVES: In this study, we evaluated (a) the contribution of SLCO1B3 and UGT1A polymorphisms to the pharmacokinetics of telmisartan in two forms, a microdose (MD) and a therapeutic dose (TD); (b) linkage disequilibrium (LD) between UGT1A1 and UGT1A3; and (c) linearity in the pharmacokinetics of telmisartan between the two forms. METHODS: Telmisartan was orally administered at MD condition (100 µg), and then at TD condition (80 mg) to 33 healthy volunteers whose genotypes were prescreened by DMET Plus. Plasma concentrations of telmisartan and its glucuronide were measured by LC-MS/MS, and population pharmacokinetic analysis was performed. RESULTS: No obvious effect of SLCO1B3 polymorphisms (334T>G, 699G>A, and rs11045585) on the pharmacokinetics of telmisartan was observed. The strong LD between UGT1A1*6 and UGT1A3*4a, and between UGT1A1*28 and UGT1A3*2a were observed. After both MD and TD administration, the mean area under the curve0-24 (±standard deviation) of telmisartan was significantly lower and higher in individuals with the UGT1A3*2a (TD, 1701±970 ng hr/ml; MD, 978±537 pg hr/ml) and *4a variants (TD, 5340±1168; MD, 3145±1093), respectively, compared with those in individuals with UGT1A3*1/*1 (TD, 2969±1456; MD, 1669±726). These results were quantitatively confirmed by population pharmacokinetic analysis. Nonlinearity of the dose-exposure relationship was observed between the MD and TD. CONCLUSION: The haplotypes of UGT1A3 significantly influenced pharmacokinetics of telmisartan and a strong LD between UGT1A1 genotype and UGT1A3 haplotype was observed. These findings are potentially of pharmacological and toxicological importance to the development and clinical use of drugs.

Delayed neutralizing antibody response in the acute phase correlates with severe progression of COVID-19.

Adaptive immunity to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) dynamics remain largely unknown. The neutralizing antibody (NAb) levels in patients with coronavirus disease 2019 (COVID-19) are helpful for understanding the pathology. Using SARS-CoV-2 pseudotyped virus, serum sample neutralization values in symptomatic COVID-19 patients were measured using the chemiluminescence reduction neutralization test (CRNT). At least two sequential serum samples collected during hospitalization were analyzed to assess NAbs neutralizing activity dynamics at different time points. Of the 11 patients, four (36.4%), six (54.5%), and one (9.1%) had moderate, severe, and critical disease, respectively. Fifty percent neutralization (N50%-CRNT) was observed upon admission in 90.9% (10/11); all patients acquired neutralizing activity 2-12 days after onset. In patients with moderate disease, neutralization was observed at earliest within two days after symptom onset. In patients with severe-to-critical disease, neutralization activity increased, plateauing 9-16 days after onset. Neutralization activity on admission was significantly higher in patients with moderate disease than in patients with severe-to-critical disease (relative % of infectivity, 6.4% vs. 41.1%; P = .011). Neutralization activity on admission inversely correlated with disease severity. The rapid NAb response may play a crucial role in preventing the progression of COVID-19.

M Segment-Based Minigenome System of Severe Fever with Thrombocytopenia Syndrome Virus as a Tool for Antiviral Drug Screening.

Severe fever with thrombocytopenia syndrome virus (SFTSV) is an emerging tick-borne bunyavirus that causes severe disease in humans with case fatality rates of approximately 30%. There are few treatment options for SFTSV infection. SFTSV RNA synthesis is conducted using a virus-encoded complex with RNA-dependent RNA polymerase activity that is required for viral propagation. This complex and its activities are, therefore, potential antiviral targets. A library of small molecule compounds was processed using a high-throughput screening (HTS) based on an SFTSV minigenome assay (MGA) in a 96-well microplate format to identify potential lead inhibitors of SFTSV RNA synthesis. The assay confirmed inhibitory activities of previously reported SFTSV inhibitors, favipiravir and ribavirin. A small-scale screening using MGA identified four candidate inhibitors that inhibited SFTSV minigenome activity by more than 80% while exhibiting less than 20% cell cytotoxicity with selectivity index (SI) values of more than 100. These included mycophenolate mofetil, methotrexate, clofarabine, and bleomycin. Overall, these data demonstrate that the SFTSV MGA is useful for anti-SFTSV drug development research.

Characterization of pseudotyped vesicular stomatitis virus bearing the heartland virus envelope glycoprotein.

The heartland virus (HRTV) is a novel phlebovirus that causes severe infections in the USA and closely related to the severe fever thrombocytopenia syndrome virus (SFTSV), a causative agent for SFTS in Asia. The entry mechanisms of HRTV remain unclear. Here, we developed the pseudotyped vesicular stomatitis virus bearing the HRTV glycoprotein (GP) (HRTVpv), and the antigenicity and the entry mechanisms of HRTV were analyzed. HRTVpv was neutralized by anti-SFTSV Gc antibody, but not the anti-SFTSV Gn antibodies. Entry of HRTVpv to cells was inhibited by bafilomycin A1 and dynasore, and but it was enhanced in cells overexpressed with C-type lectins. Production of infectious HRTVpv and SFTSVpv was reduced by Nn-DNJ, α-glucosidase inhibitor. The entry of HRTV occurs via pH- and dynamin-dependent endocytosis. Furthermore, Nn-DNJ may be a possible therapeutic agent against HRTV and SFTSV.

[Development of automatic navigation measuring system using template-matching software in image guided neurosurgery].

An image-guided neurosurgery and neuronavigation system based on magnetic resonance imaging has been used as an indispensable tool for resection of brain tumors. Therefore, accuracy of the neuronavigation system, provided by periodic quality assurance (QA), is essential for image-guided neurosurgery. Two types of accuracy index, fiducial registration error (FRE) and target registration error (TRE), have been used to evaluate navigation accuracy. FRE shows navigation accuracy on points that have been registered. On the other hand, TRE shows navigation accuracy on points such as tumor, skin, and fiducial markers. This study shows that TRE is more reliable than FRE. However, calculation of TRE is a time-consuming, subjective task. Software for QA was developed to compute TRE. This software calculates TRE automatically by an image processing technique, such as automatic template matching. TRE was calculated by the software and compared with the results obtained by manual calculation. Using the software made it possible to achieve a reliable QA system.